All these changes should have no side-effects or change behavior:
- Use bytes.Buffer's String() instead of a conversion
- Use time.Since and time.Until where fitting
- Drop unnecessary returns and assignment
* Add ui-content-path flag
* tests complete, regex validator on string, index.html updated
* cleaning up debugging stuff
* ui: Enable ember environment configuration to be set via the go binary at runtime (#5934)
* ui: Only inject {{.ContentPath}} if we are makeing a prod build...
...otherwise we just use the current rootURL
This gets injected into a <base /> node which solves the assets path
problem but not the ember problem
* ui: Pull out the <base href=""> value and inject it into ember env
See previous commit:
The <base href=""> value is 'sometimes' injected from go at index
serve time. We pass this value down to ember by overwriting the ember
config that is injected via a <meta> tag. This has to be done before
ember bootup.
Sometimes (during testing and development, basically not production)
this is injected with the already existing value, in which case this
essentially changes nothing.
The code here is slightly abstracted away from our specific usage to
make it easier for anyone else to use, and also make sure we can cope
with using this same method to pass variables down from the CLI through
to ember in the future.
* ui: We can't use <base /> move everything to javascript (#5941)
Unfortuantely we can't seem to be able to use <base> and rootURL
together as URL paths will get doubled up (`ui/ui/`).
This moves all the things that we need to interpolate with .ContentPath
to the `startup` javascript so we can conditionally print out
`{{.ContentPath}}` in lots of places (now we can't use base)
* fixed when we serve index.html
* ui: For writing a ContentPath, we also need to cope with testing... (#5945)
...and potentially more environments
Testing has more additional things in a separate index.html in `tests/`
This make the entire thing a little saner and uses just javascriopt
template literals instead of a pseudo handbrake synatx for our
templating of these files.
Intead of just templating the entire file this way, we still only
template `{{content-for 'head'}}` and `{{content-for 'body'}}`
in this way to ensure we support other plugins/addons
* build: Loosen up the regex for retrieving the CONSUL_VERSION (#5946)
* build: Loosen up the regex for retrieving the CONSUL_VERSION
1. Previously the `sed` replacement was searching for the CONSUL_VERSION
comment at the start of a line, it no longer does this to allow for
indentation.
2. Both `grep` and `sed` where looking for the omment at the end of the
line. We've removed this restriction here. We don't need to remove it
right now, but if we ever put the comment followed by something here the
searching would break.
3. Added `xargs` for trimming the resulting version string. We aren't
using this already in the rest of the scripts, but we are pretty sure
this is available on most systems.
* ui: Fix erroneous variable, and also force an ember cache clean on build
1. We referenced a variable incorrectly here, this fixes that.
2. We also made sure that every `make` target clears ember's `tmp` cache
to ensure that its not using any caches that have since been edited
everytime we call a `make` target.
* added docs, fixed encoding
* fixed go fmt
* Update agent/config/config.go
Co-Authored-By: R.B. Boyer <public@richardboyer.net>
* Completed Suggestions
* run gofmt on http.go
* fix testsanitize
* fix fullconfig/hcl by setting correct 'want'
* ran gofmt on agent/config/runtime_test.go
* Update website/source/docs/agent/options.html.md
Co-Authored-By: Hans Hasselberg <me@hans.io>
* Update website/source/docs/agent/options.html.md
Co-Authored-By: kaitlincarter-hc <43049322+kaitlincarter-hc@users.noreply.github.com>
* remove contentpath from redirectFS struct
Fixes: #4222
# Data Filtering
This PR will implement filtering for the following endpoints:
## Supported HTTP Endpoints
- `/agent/checks`
- `/agent/services`
- `/catalog/nodes`
- `/catalog/service/:service`
- `/catalog/connect/:service`
- `/catalog/node/:node`
- `/health/node/:node`
- `/health/checks/:service`
- `/health/service/:service`
- `/health/connect/:service`
- `/health/state/:state`
- `/internal/ui/nodes`
- `/internal/ui/services`
More can be added going forward and any endpoint which is used to list some data is a good candidate.
## Usage
When using the HTTP API a `filter` query parameter can be used to pass a filter expression to Consul. Filter Expressions take the general form of:
```
<selector> == <value>
<selector> != <value>
<value> in <selector>
<value> not in <selector>
<selector> contains <value>
<selector> not contains <value>
<selector> is empty
<selector> is not empty
not <other expression>
<expression 1> and <expression 2>
<expression 1> or <expression 2>
```
Normal boolean logic and precedence is supported. All of the actual filtering and evaluation logic is coming from the [go-bexpr](https://github.com/hashicorp/go-bexpr) library
## Other changes
Adding the `Internal.ServiceDump` RPC endpoint. This will allow the UI to filter services better.
* Support rate limiting and concurrency limiting CSR requests on servers; handle CA rotations gracefully with jitter and backoff-on-rate-limit in client
* Add CSR rate limiting docs
* Fix config naming and add tests for new CA configs
This endpoint aggregates all checks related to <service id> on the agent
and return an appropriate http code + the string describing the worst
check.
This allows to cleanly expose service status to other component, hiding
complexity of multiple checks.
This is especially useful to use consul to feed a load balancer which
would delegate health checking to consul agent.
Exposing this endpoint on the agent is necessary to avoid a hit on
consul servers and avoid decreasing resiliency (this endpoint will work
even if there is no consul leader in the cluster).
This PR is almost a complete rewrite of the ACL system within Consul. It brings the features more in line with other HashiCorp products. Obviously there is quite a bit left to do here but most of it is related docs, testing and finishing the last few commands in the CLI. I will update the PR description and check off the todos as I finish them over the next few days/week.
Description
At a high level this PR is mainly to split ACL tokens from Policies and to split the concepts of Authorization from Identities. A lot of this PR is mostly just to support CRUD operations on ACLTokens and ACLPolicies. These in and of themselves are not particularly interesting. The bigger conceptual changes are in how tokens get resolved, how backwards compatibility is handled and the separation of policy from identity which could lead the way to allowing for alternative identity providers.
On the surface and with a new cluster the ACL system will look very similar to that of Nomads. Both have tokens and policies. Both have local tokens. The ACL management APIs for both are very similar. I even ripped off Nomad's ACL bootstrap resetting procedure. There are a few key differences though.
Nomad requires token and policy replication where Consul only requires policy replication with token replication being opt-in. In Consul local tokens only work with token replication being enabled though.
All policies in Nomad are globally applicable. In Consul all policies are stored and replicated globally but can be scoped to a subset of the datacenters. This allows for more granular access management.
Unlike Nomad, Consul has legacy baggage in the form of the original ACL system. The ramifications of this are:
A server running the new system must still support other clients using the legacy system.
A client running the new system must be able to use the legacy RPCs when the servers in its datacenter are running the legacy system.
The primary ACL DC's servers running in legacy mode needs to be a gate that keeps everything else in the entire multi-DC cluster running in legacy mode.
So not only does this PR implement the new ACL system but has a legacy mode built in for when the cluster isn't ready for new ACLs. Also detecting that new ACLs can be used is automatic and requires no configuration on the part of administrators. This process is detailed more in the "Transitioning from Legacy to New ACL Mode" section below.
* agent/debug: add package for debugging, host info
* api: add v1/agent/host endpoint
* agent: add v1/agent/host endpoint
* command/debug: implementation of static capture
* command/debug: tests and only configured targets
* agent/debug: add basic test for host metrics
* command/debug: add methods for dynamic data capture
* api: add debug/pprof endpoints
* command/debug: add pprof
* command/debug: timing, wg, logs to disk
* vendor: add gopsutil/disk
* command/debug: add a usage section
* website: add docs for consul debug
* agent/host: require operator:read
* api/host: improve docs and no retry timing
* command/debug: fail on extra arguments
* command/debug: fixup file permissions to 0644
* command/debug: remove server flags
* command/debug: improve clarity of usage section
* api/debug: add Trace for profiling, fix profile
* command/debug: capture profile and trace at the same time
* command/debug: add index document
* command/debug: use "clusters" in place of members
* command/debug: remove address in output
* command/debug: improve comment on metrics sleep
* command/debug: clarify usage
* agent: always register pprof handlers and protect
This will allow us to avoid a restart of a target agent
for profiling by always registering the pprof handlers.
Given this is a potentially sensitive path, it is protected
with an operator:read ACL and enable debug being
set to true on the target agent. enable_debug still requires
a restart.
If ACLs are disabled, enable_debug is sufficient.
* command/debug: use trace.out instead of .prof
More in line with golang docs.
* agent: fix comment wording
* agent: wrap table driven tests in t.run()
* Plumb xDS server and proxyxfg into the agent startup
* Add `consul connect envoy` command to allow running Envoy as a connect sidecar.
* Add test for help tabs; typos and style fixups from review
* Add cache types for catalog/services and health/services and basic test that caching works
* Support non-blocking cache types with Cache-Control semantics.
* Update API docs to include caching info for every endpoint.
* Comment updates per PR feedback.
* Add note on caching to the 10,000 foot view on the architecture page to make the new data path more clear.
* Document prepared query staleness quirk and force all background requests to AllowStale so we can spread service discovery load across servers.
Fixes: #4441
This fixes the issue with Connect Managed Proxies + ACLs being broken.
The underlying problem was that the token parsed for most http endpoints was sent untouched to the servers via the RPC request. These changes make it so that at the HTTP endpoint when parsing the token we additionally attempt to convert potential proxy tokens into regular tokens before sending to the RPC endpoint. Proxy tokens are only valid on the agent with the managed proxy so the resolution has to happen before it gets forwarded anywhere.
Few other fixes in here just to get a clean run locally - they are all also fixed in other PRs but shouldn't conflict.
This should be robust to timing between goroutines now.
* Move settings to use the same service/route API as the rest of the app
* Put some ideas down for unit testing on adapters
* Favour `Model` over `Entity`
* Move away from using `reopen` to using Mixins
* Amend messages, comment/document some usage
* Make sure the returns are consistent in normalizePayload, also
Add some todo's in to remind me to think consider this further at a
later date. For example, is normalizePayload to be a hook or an
overridable method
* Start stripping back the HTML to semantics
* Use a variable rather than chaining
* Remove unused helpers
* Start picking through the new designs, start with listing pages
* First draft HTML for every page
* Making progress on the CSS
* Keep plugging away at the catalog css
* Looking at scrolling
* Wire up filtering
* Sort out filter counting, more or less done a few outstanding
* Start knocking the forms into shape
* Add in codemirror
* Keep moving forwards with the form like layouts
* Start looking at ACL editing page, add footer in
* Pull the filters back in, look at an autoresizer for scroll views
* First draft toggles
* 2nd draft healthcheck icons
* Tweak node healthcheck icons
* Looking at healthcheck detail icons
* Tweak the filter-bar and add selections to the in content tabs
* Add ACL create, pill-like acl type highlight
* Tweaking the main nav some more
* Working on the filter-bar and freetext-filter
* Masonry layout
* Stick with `checks` instead of healthy/unhealthy
* Fix up the filter numbers/counts
* Use the thead for a measure
* First draft tomography back in
* First draft DC dropdown
* Add a temporary create buttong to kv's
* Move KV and ACL to use a create page
* Move tags
* Run through old tests
* Injectable server
* Start adding test attributes
* Add some page objects
* More test attributes and pages
* Acl filter objects
* Add a page.. page object
* Clickable items in lists
* Add rest/spread babel plugin, remove mirage for now
* Add fix for ember-collection
* Keep track of acl filters
* ember-cli-page-object
* ember-test-selectors
* ui: update version of ui compile deps
* Update static assets
* Centralize radiogroup helper
* Rejig KV's and begin to clean it up
* Work around lack of Tags for the moment..
* Some little css tweaks and start to remove possibles
* Working on the dc page and incidentals
1. Sort the datacenter-picker list
2. Add a selected state to the datacenter-picker
3. Make dc an {Name: dc}
4. Add an env helper to get to 'env vars' from within templates
* Click outside stuff for the datacenter-picker, is-active on nav
* Make sure the dropdown CTA can be active
* Bump ember add pluralize helper
* Little try at sass based custom queries
* Rejig tablular collection so it deals with resizing, actions
1. WIP: start building actions dropdowns
2. Move tabular collection to deal with resizing to rule out differences
* First draft actions dropdowns
* Add ports, selectable IP's
* Flash messages, plus general cleanup/consistency
1. Add ember-cli-flash for flash messages
2. Move everything to get() instead of item.get
3. Spotted a few things that weren't consistent
* DOn't go lower than zero
* First draft vertical menu
* Missed a get, tweak dropmenu tick
* Big cleanup
1. this.get(), this.set() > get(), set()
2. assign > {...{}, ...{}}
3. Seperator > separator
* WIP: settings
* Moved things into a ui-v2 folder
* Decide on a way to do the settings page whilst maintaining the url + dc's
* Start some error pages
* Remove base64 polyfill
* Tie in settings, fix atob bug, tweak layout css
* Centralize confirmations into a component
* Allow switching between the old and new UI with the CONSUL_UI_BETA env var
Currently all the assets are packaged into a single AssetFS and a prefix is configured to switch between the two.
* Attempt at some updates to integrate the v2 ui build into the main infrastructure
* Add redirect to index.html for unknown paths
* Allow redictor to /index.html for new ui when using -ui-dir
* Take ACLs to the correct place on save
* First pass breadcrumbs
* Remove datacenter selector on the index page
* Tweak overall layout
* Make buttons 'resets'
* Tweak last DC stuff
* Validations plus kv keyname viewing tweaks
* Pull sessions back in
* Tweak the env vars to be more reusable
* Move isAnon to the view
* No items and disabled acl css
* ACL and KV details
1. Unauthorized page
2. Make sure the ACL is always selected when it needs it
3. Check record deletion with a changeset
* Few more acl tweaks/corrections
* Add no items view to node > services
* Tags for node > services
* Make sure we have tags
* Fix up the labels on the tomography graph
* Add node link (agent) to kv sessions
* Duplicate up `create` for KV 'root creation'
* Safety check for health checks
* Fix up the grids
* Truncate td a's, fix kv columns
* Watch for spaces in KV id's
* Move actions to their own mixins for now at least
* Link reset to settings incase I want to type it in
* Tweak error page
* Cleanup healthcheck icons in service listing
* Centralize errors and make getting back easier
* Nice numbers
* Compact buttons
* Some incidental css cleanups
* Use 'Key / Value' for root
* Tweak tomography layout
* Fix single healthcheck unhealthy resource
* Get loading screen ready
* Fix healthy healthcheck tick
* Everything in header starts white
* First draft loader
* Refactor the entire backend to use proper unique keys, plus..
1. Make unique keys form dc + slug (uid)
2. Fun with errors...
* Tweak header colors
* Add noopener noreferrer to external links
* Add supers to setupController
* Implement cloning, using ember-data...
* Move the more expensive down the switch order
* First draft empty record cleanup..
* Add the cusomt store test
* Temporarily use the htmlSafe prototype to remove the console warning
* Encode hashes in urls
* Go back to using title for errors for now
* Start removing unused bulma
* Lint
* WIP: Start looking at failing tests
* Remove single redirect test
* Finish off error message styling
* Add full ember-data cache invalidation to avoid stale data...
* Add uncolorable warning icons
* More info icon
* Rearrange single service, plus tag printing
* Logo
* No quotes
* Add a simple startup logo
* Tweak healthcheck statuses
* Fix border-color for healthchecks
* Tweak node tabs
* Catch 401 ACL errors and rethrow with the provided error message
* Remove old acl unauth and error routes
* Missed a super
* Make 'All' refer to number of checks, not services
* Remove ember-resizer, add autoprefixer
* Don't show tomography if its not worth it, viewify it more also
* Little model cleanup
* Chevrons
* Find a way to reliably set the class of html from the view
* Consistent html
* Make sure session id's are visible as long as possible
* Fix single service check count
* Add filters and searchs to the query string
* Don't remember the selected tab
* Change text
* Eror tweaking
* Use chevrons on all breadcrumbs even in kv's
* Clean up a file
* Tweak some messaging
* Makesure the footer overlays whats in the page
* Tweak KV errors
* Move json toggle over to the right
* feedback-dialog along with copy buttons
* Better confirmation dialogs
* Add git sha comment
* Same title as old UI
* Allow defaults
* Make sure value is a string
* WIP: Scrolling dropdowns/confirmations
* Add to kv's
* Remove set
* First pass trace
* Better table rows
* Pull over the hashi code editor styles
* Editor tweaks
* Responsive tabs
* Add number formatting to tomography
* Review whats left todo
* Lint
* Add a coordinate ember data triplet
* Bump in a v2.0.0
* Update old tests
* Get coverage working again
* Make sure query keys are also encoded
* Don't test console.error
* Unit test some more utils
* Tweak the size of the tabular collections
* Clean up gitignore
* Fix copy button rollovers
* Get healthcheck 'icon icons' onto the text baseline
* Tweak healthcheck padding and alignment
* Make sure commas kick in in rtt, probably never get to that
* Improve vertical menu
* Tweak dropdown active state to not have a bg
* Tweak paddings
* Search entire string not just 'startsWith'
* Button states
* Most buttons have 1px border
* More button tweaks
* You can only view kv folders
* CSS cleanup reduction
* Form input states and little cleanup
* More CSS reduction
* Sort checks by importance
* Fix click outside on datacenter picker
* Make sure table th's also auto calculate properly
* Make sure `json` isn't remembered in KV editing
* Fix recursive deletion in KV's
* Centralize size
* Catch updateRecord
* Don't double envode
* model > item consistency
* Action loading and ACL tweaks
* Add settings dependencies to acl tests
* Better loading
* utf-8 base64 encode/decode
* Don't hang off a prototype for htmlSafe
* Missing base64 files...
* Get atob/btoa polyfill right
* Shadowy rollovers
* Disabled button styling for primaries
* autofocuses only onload for now
* Fix footer centering
* Beginning of 'notices'
* Remove the isLocked disabling as we are letting you do what the API does
* Don't forget the documentation link for sessions
* Updates are more likely
* Use exported constant
* Dont export redirectFS and a few other PR updates
* Remove the old bootstrap config which was used for the old UI skin
* Use curlies for multiple properties
Update docs a little
Update/add tests. Make sure all the various ways of determining the source IP work
Update X-Forwarded-For header parsing. This can be a comma separated list with the first element being the original IP so we now handle csv data there.
Got rid of error return from sourceAddrFromRequest
Also fixed an issue where we need to have the X-Forwarded-For header processed before the RemoteAddr. This shouldn’t have any functional difference for prod code but for mocked request objects it allows them to work.
The need has been spotted in issue https://github.com/hashicorp/consul/issues/3687.
Using "NYTimes/gziphandler", the http api responses can now be compressed if required.
The Go API requires compressed response if possible and handle the compressed response.
We here change only the http api (not the UI for instance).
- register endpoints with supported methods
- support OPTIONS requests, indicating supported methods
- extract method validation (error 405) from individual endpoints
- on 405 where multiple methods are allowed, create a single Allow
header with comma-separated values, not multiple Allow headers.
* Refactors the HTTP listen path to create servers in the same spot.
* Adds HTTP/2 support to Consul's HTTPS server.
* Vendors Go HTTP/2 library and associated deps.
This patch adds a /v1/coordinate/node/:node endpoint to get the network
coordinates for a single node in the network.
Since Consul Enterprise supports network segments it is still possible
to receive mutiple entries for a single node - one per segment.
* agent: consolidate http method not allowed checks
This patch uses the error handling of the http handlers to handle HTTP
method not allowed errors across all available endpoints. It also adds a
test for testing whether the endpoints respond with the correct status
code.
* agent: do not panic on metrics tests
* agent: drop other tests for MethodNotAllowed
* agent: align /agent/join with reality
/agent/join uses PUT instead of GET as documented.
* agent: align /agent/check/{fail,warn,pass} with reality
/agent/check/{fail,warn,pass} uses PUT instead of GET as documented.
* fix some tests
* Drop more tests for method not allowed
* Align TestAgent_RegisterService_InvalidAddress with reality
* Changes API client join to use PUT instead of GET.
* Fixes agent endpoint verbs and removes obsolete tests.
* Updates the change log.
* new config parser for agent
This patch implements a new config parser for the consul agent which
makes the following changes to the previous implementation:
* add HCL support
* all configuration fragments in tests and for default config are
expressed as HCL fragments
* HCL fragments can be provided on the command line so that they
can eventually replace the command line flags.
* HCL/JSON fragments are parsed into a temporary Config structure
which can be merged using reflection (all values are pointers).
The existing merge logic of overwrite for values and append
for slices has been preserved.
* A single builder process generates a typed runtime configuration
for the agent.
The new implementation is more strict and fails in the builder process
if no valid runtime configuration can be generated. Therefore,
additional validations in other parts of the code should be removed.
The builder also pre-computes all required network addresses so that no
address/port magic should be required where the configuration is used
and should therefore be removed.
* Upgrade github.com/hashicorp/hcl to support int64
* improve error messages
* fix directory permission test
* Fix rtt test
* Fix ForceLeave test
* Skip performance test for now until we know what to do
* Update github.com/hashicorp/memberlist to update log prefix
* Make memberlist use the default logger
* improve config error handling
* do not fail on non-existing data-dir
* experiment with non-uniform timeouts to get a handle on stalled leader elections
* Run tests for packages separately to eliminate the spurious port conflicts
* refactor private address detection and unify approach for ipv4 and ipv6.
Fixes#2825
* do not allow unix sockets for DNS
* improve bind and advertise addr error handling
* go through builder using test coverage
* minimal update to the docs
* more coverage tests fixed
* more tests
* fix makefile
* cleanup
* fix port conflicts with external port server 'porter'
* stop test server on error
* do not run api test that change global ENV concurrently with the other tests
* Run remaining api tests concurrently
* no need for retry with the port number service
* monkey patch race condition in go-sockaddr until we understand why that fails
* monkey patch hcl decoder race condidtion until we understand why that fails
* monkey patch spurious errors in strings.EqualFold from here
* add test for hcl decoder race condition. Run with go test -parallel 128
* Increase timeout again
* cleanup
* don't log port allocations by default
* use base command arg parsing to format help output properly
* handle -dc deprecation case in Build
* switch autopilot.max_trailing_logs to int
* remove duplicate test case
* remove unused methods
* remove comments about flag/config value inconsistencies
* switch got and want around since the error message was misleading.
* Removes a stray debug log.
* Removes a stray newline in imports.
* Fixes TestACL_Version8.
* Runs go fmt.
* Adds a default case for unknown address types.
* Reoders and reformats some imports.
* Adds some comments and fixes typos.
* Reorders imports.
* add unix socket support for dns later
* drop all deprecated flags and arguments
* fix wrong field name
* remove stray node-id file
* drop unnecessary patch section in test
* drop duplicate test
* add test for LeaveOnTerm and SkipLeaveOnInt in client mode
* drop "bla" and add clarifying comment for the test
* split up tests to support enterprise/non-enterprise tests
* drop raft multiplier and derive values during build phase
* sanitize runtime config reflectively and add test
* detect invalid config fields
* fix tests with invalid config fields
* use different values for wan sanitiziation test
* drop recursor in favor of recursors
* allow dns_config.udp_answer_limit to be zero
* make sure tests run on machines with multiple ips
* Fix failing tests in a few more places by providing a bind address in the test
* Gets rid of skipped TestAgent_CheckPerformanceSettings and adds case for builder.
* Add porter to server_test.go to make tests there less flaky
* go fmt
* Added rate limiting for agent RPC calls.
* Initializes the rate limiter based on the config.
* Adds the rate limiter into the snapshot RPC path.
* Adds unit tests for the RPC rate limiter.
* Groups the RPC limit parameters under "limits" in the config.
* Adds some documentation about the RPC limiter.
* Sends a 429 response when the rate limiter kicks in.
* Adds docs for new telemetry.
* Makes snapshot telemetry look like RPC telemetry and cleans up comments.
The error handling of the ACL code relies on the presence of certain
magic error messages. Since the error values are sent via RPC between
older and newer consul agents we cannot just replace the magic values
with typed errors and switch to type checks since this would break
compatibility with older clients.
Therefore, this patch moves all magic ACL error messages into the acl
package and provides default error values and helper functions which
determine the type of error.
* Obfuscates ACL tokens appearing in /v1/acl APIs.
* Makes test positively identify the desired strings.
* Adds an example and explanation of the regular expression.
This patch adds an "http_config" object to the config file
and moves the "http_api_response_headers" option there.
"http_api_response_headers" is now deprecated in favor of
"http_config.response_headers"
Christian Muehlhaeuser
Sarah Christoff
Matt Keeler
Freddy
Kyle Havlovitz
Paul Banks
Aestek
Grégoire Seux
Hans Hasselberg
Jack Pearkes
Miroslav Bagljas
mkeeler
Mitchell Hashimoto
John Cowen
Yoann
Preetha
Edd Steel
Diptanu Choudhury
James Phillips
Frank Schroeder
Ryan Slade
wojtkiewicz